Abstract

A scheme for anonymous tag based anonymous credentials is enhanced. Different from zero knowledge proof based anonymous credential schemes that require numbers of challenges and responses between verifiers and credential holders, the anonymous tag based scheme requires only small number of challenges and responses. However, the original scheme has probabilistic features, i.e. verifiers must generate dummy fake challenges; therefore overheads for managing anonymous systems cannot be reduced to the minimum. The enhanced scheme proposed in this paper excludes these probabilistic features from interactions between verifiers and credential holders. The scheme also corrects several design errors included in the original scheme.